From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4FE6EC19F2D for ; Tue, 9 Aug 2022 08:57:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241979AbiHII5P (ORCPT ); Tue, 9 Aug 2022 04:57:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241485AbiHII4t (ORCPT ); Tue, 9 Aug 2022 04:56:49 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2ADEF2252D; Tue, 9 Aug 2022 01:56:47 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D55C5B80E11; Tue, 9 Aug 2022 08:56:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85606C433C1; Tue, 9 Aug 2022 08:56:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660035404; bh=5UfhFW8R3mc4/i0CbqCEm7Z2hfhkjOqWFTVdTW1KEos=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=iE2wEKtr2NR09x9UoLHFPRZGUQ08Lt79ntrYBu+nF9VtEnjnlbD7/TyeQoDquiKxF DAn79ymhs0TCZDQ68KrMb3y9TVi34kaFMYHp5AzZOwVdoB9HQm6alFSVbGzRIHY1Bl f/5B7zPdEDvqhExncNQq7Te++/PyKJEMtlBF3KpAk5H7vH1jEY0kvTZV7MxGKf9a8Y f9UoR+ixdDTDQ6dK+i9Gsv/CN0P3kmdCOWak1wtLNKnZascfRnXJnhOD4RY+jj4bbI kOPUKl6p3s5vauLsZ3fUroFxVXROtCTv2vWPKvdFgPNc9PAjOhKrqJp0KJKljUkbdG 1hci70Fl1x9Og== Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1oLL2Y-001sCa-C4; Tue, 09 Aug 2022 09:56:42 +0100 Date: Tue, 09 Aug 2022 09:56:42 +0100 Message-ID: <874jylx0ad.wl-maz@kernel.org> From: Marc Zyngier To: Huacai Chen Cc: Huacai Chen , Thomas Gleixner , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Xuerui Wang , Xuefeng Li , Jiaxun Yang Subject: Re: [PATCH] LoongArch: Don't disable EIOINTC master core In-Reply-To: <20220809074522.2444672-1-chenhuacai@loongson.cn> References: <20220809074522.2444672-1-chenhuacai@loongson.cn> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: chenhuacai@loongson.cn, chenhuacai@kernel.org, tglx@linutronix.de, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@xen0n.name, lixuefeng@loongson.cn, jiaxun.yang@flygoat.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Tue, 09 Aug 2022 08:45:22 +0100, Huacai Chen wrote: > > This patch fix a CPU hotplug issue. The EIOINTC master core (the first > core of an EIOINTC node) should not be disabled at runtime, since it has > the responsibility of dispatching I/O interrupts. > > Signed-off-by: Huacai Chen > --- > arch/loongarch/kernel/smp.c | 9 +++++++++ > drivers/irqchip/irq-loongson-eiointc.c | 5 +++++ > 2 files changed, 14 insertions(+) > > diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c > index 09743103d9b3..54901716f8de 100644 > --- a/arch/loongarch/kernel/smp.c > +++ b/arch/loongarch/kernel/smp.c > @@ -242,9 +242,18 @@ void loongson3_smp_finish(void) > > static bool io_master(int cpu) > { > + int i, node, master; > + > if (cpu == 0) > return true; > > + for (i = 1; i < loongson_sysconf.nr_io_pics; i++) { > + node = eiointc_get_node(i); > + master = cpu_number_map(node * CORES_PER_EIO_NODE); > + if (cpu == master) > + return true; > + } > + > return false; > } > > diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c > index 170dbc96c7d3..6c99a2ff95f5 100644 > --- a/drivers/irqchip/irq-loongson-eiointc.c > +++ b/drivers/irqchip/irq-loongson-eiointc.c > @@ -56,6 +56,11 @@ static void eiointc_enable(void) > iocsr_write64(misc, LOONGARCH_IOCSR_MISC_FUNC); > } > > +int eiointc_get_node(int id) > +{ > + return eiointc_priv[id]->node; > +} > + > static int cpu_to_eio_node(int cpu) > { > return cpu_logical_map(cpu) / CORES_PER_EIO_NODE; I don't understand why it has to be this complex and make any use of the node number. As I understand it, CPU-0 in any EIOINTC block is a master. So all you need to find out is whether the CPU number is a multiple of CORES_PER_EIO_NODE. Something like: return (cpu_logical_map(cpu) % CORES_PER_EIO_NODE) == 0; which doesn't require exporting anything from anywhere? M. -- Without deviation from the norm, progress is not possible.